With the ever-increasing fuel shortage, it becomes more and more necessary to find ways to conserve energy in the home. One way, of course, is through additional insulation. Another source of energy savings is to increase the efficiency of the home heating system. In the average gas or oil-fired home heating system, a considerable amount of heat generated by the burner which heats the air or water circulated throughout the house is vented through the stack or chimney to the atmosphere and is, therefore, wasted.
There have been some attempts to recapture this heat by utilizing various heat exchange structures built into the heater or flue which use the hot products of combustion to heat fresh air and releasing the heated fresh air into the living space. Examples of such structures are disclosed in the following U.S. patents:
U.S. Pat. No. 2,361,643 PA1 U.S. Pat. No. 2,385,652 PA1 U.S. Pat. No. 2,479,413 PA1 U.S. Pat. No. 2,910,276 PA1 U.S. Pat. No. 2,962,218 PA1 U.S. Pat. No. 4,138,062
While those prior structures at least appear able to produce some energy savings in the home, they have certain disadvantages which limit their use and application. Some of those conventional heat exchange devices have to be incorporated right into the heater or boiler at the time it is made. Therefore, they can't be retrofit on existing heaters in the home. Some of those prior structures are quite complicated and therefore expensive. Some others rely on counterflow of cool air in the chimney in order to operate properly. In other words, fresh air is drawn from the top of the chimney all the way down to the heater and then recirculated back up through the chimney again. This not only complicates the heat exchange system, it also requires the system to have a large, energy consuming blower to obtain the requisite air circulation. Further, the incoming cold air cools the upper end of the chimney flue pipe excessively degrading the effectiveness of the heat exchanger as a whole.